US2038131A - Lubricating system for compressors - Google Patents

Description

April 21, 1936. E, R A 2,038,131

LUBRIJGATINGY SYSTEM FOR COMPRESSORS Filed Aug. 19, 1955 2 Sheets-Sheet l' A INVENTOR William Edward Ric/10rd I BY" v ATTORNEY April 21, 1936.

W. E. RICHARD LUBRICATING SYSTEM FOR COMPRESSORS Filed Aug. 19, 1935 2 Sheets-Sheet 2 INVENTOR Will/am Edward/iichard M ATTOR EY Patented Apr. 21, 1936 UNITED STATES PATENT OFF-ICE This invention relates to improvements in a lubricating system for compressors, and has for its object the provision of a lubricating system that will be simple and efflcient, which will sup- 5 .ply adequate lubrication to the working parts of the compressor, its driving motor and the seal for the shaft if one is used.

Other objects will be apparent from the following specification, the invention consisting substantially in the construction, combination, location and relative arrangement of parts, all as will be more fully hereinafter set forth, as shown by the accompanying drawings, and' finally pointed out in the appended claims. For the sake of illustration, the invention will be described as applied to a compressor unit as commonly used in connection with refrigeration systems, such as small motor driven household refrigerators. Such a unit is more fully described in the copending application Serial No. 654,383, filed January 31, 1 933, and entitled Refrigeration apparatus. It will be obvious, however, that the invention may be applied to any type of compressor or pump, or any other device having a shaft and bearings it is desired to lubricate, provided said device is capable of creating a suction or vacuum as hereinafter referred to.

In the accompanying drawings:

Figure 1 is a cross sectional view of a motorcompressor unit embodying the invention, of the type shown in the aforesaid copending application and having a seal about the driving shaft to prevent egressof fluid from the casing'through I which the shaft extends; and

Figure 2 is a vertical cross sectional view of a hermetically sealed motor-compressor'unit embodying the invention, all working parts being enclosed in a. hermetically sealed casing throughwhich the compressor shaft does not extend.

The construction of the motor-compressor units, Figures 1 and 2,v may be varied within wide limits and consequently no detailed construction of the various parts is herein given exceptwhat is necessary to adequately describe the lubricating system.

A motor-compressor unit commonly employed in connection -with refrigeration systems such as that referred to in the aforesaid copending application comprises a casing I!) having an inwardly extending flange l'l adapted to support the compressor proper. The compressor may be of any suitable type, either rotary or reciprocating, and may consist of a body portion l2 having a. front end plate l3 and a rear end plate l4 bolted thereon and enclosing the usual rotor,l5 which is provided with shafts l6 and II. A cap -l8 encloses the bottom bearing as shown.

The end plate l3 when secured to the flange II by means of the bolts l9 and 20 as shown, forms a top closure for the casing l8, and i3 and Hi to- 5 gether define a closed chamber 2i containing a body of lubricant 22 in which is immersed a tube 23 having a strainer'2 l on its outer end as shown. This tube communicates with a passage 25 in the end plate l4 leading into the bearing supporting 10 shaft I]. The upwardly projecting shaft l8 has attached thereto and revolvable therewith a collar 26 which has secured thereto a sylphon bellows 21 which has secured to it the lower collar 28 which 15 is ground to seat and revolve upon a laterally extending. flange 29 of the tubular member 38 which is supported in the .end plate l3.

Shaft I6 has secured to its outer end the nut 3| which supports the motor rotor '32, an outward 20 extension of this nut supporting the cooling fan 33. A flange 34 on the casing l0 supports the stator and windings of the motor indicated by the numeral 35 which stator is held in place by means of screws 350, as shown. The upper bearing 36 is supported in the tubular member 30. r The compressor is provided with the usual inlet or suction-connection shown in dotted lines at 31 and the pressure or discharge of the compressor passes into the passage 38 in the body portion l2.

,The operation of the lubrication system will now be described. Assuming that the compressor is connected into the refrigerating system and that the motor is operating and that asupply of 35 lubricant exists at 22 and that the compressor is operating on any one of the well known refrigerants that may be used therewith which are taken into the suction 31 in a more or less gaseous state, compressed and discharged; under these 40 conditions the discharge at 38 is' comprised partly of refrigerant and partly of lubricant, and this mixture passes up passage 38 and into passage 39 in the end plate 13 and into the annular cavity 40 formed in the .end plate as shown and surrounding the tubular member 30. The annular cavity 48 is sloped downwardly as shown so as to provide a sump or pocket in which lubricant will collect, the lubricant separating out of the gas- 0 eous mixture by gravity by reason of the whirling 5 action that may be given the gas by properly sloping the passage 39 as it enters the cavity 40 from the passage 38.

As the lubricant settles in 48 it enters the hole 4| in the tubular member 38 and passes through the corresponding hole in the bearing 36, as shown, and into the interior annular groove in :lge bearing at this point, denoted by the numeral travels in two directions, first upwardly along the shaft l6 until it reaches the interior of the sylphon bellows 21 and overflowing the top of bearing 36 the lubricant passes down through the annular space between the top of the bearing and the interior of collar 28 and lubricates the ground sliding surfaces of the lower collar 28 and the flange 29 of the tubular member 30. Any excess of lubricant that finds its way to the interior of the sylphon passes down the passage 43 which connects to the suction side of the compressor. By the foregoing arrangement, the bearing 36 above the annular groove 42 is properly lubricated, as the lubricant is drawn out of the annular groove 42, up into the sylphon,'thereby lubricating the seal and is drawn down into the compressor and recirculated.

Secondly, the bearing is provided with another annular groove, as shown at 44, surrounding the shaft and communicating with the passage 43, through the hole 43a as shown in Fig. 1 and lubricant will be drawn down along the shaft from the groove 42 and into the groove 44, the excess being drawn out into passage 43 and returned to the suction side of the compressor and recirculated. This lower passage '44 therefore lubricates the bottom portion of the bearing 36. Compressed gases after leaving part of the lubricant in the bottom of the annular cavity 40,

' pass downwardly through the passage 45 and out through the opening 46 into the chamber 2| which puts a pressure on the lubricant 22 forcing lubricant through the strainer 24 into the tube 23 and through the passage 25, thereby lubricating the bottom bearing for shaft l1.

The lubricant entering the compressor via pa'ssage 43 serves to seal and lubricate the same and thus all working parts of the compressor are properly lubricated at all times.

It will be observed thatthe arrangement just described may be designed to provide a minimum pressure within the sylphon 21 so that a very light spring 21a may be used to keep the lower collar 28 in tight sealing connection with the flange 29.

The hermetically sealed unit shown in Figure 2 is of substantially the same construction as that just described except that as no seal is used, the construction of the upper bearing is simplified.

In Figure 2, the compressor discharges into passages 38 and 39, as previously described, and

into the annular cavity 40. Lubricant settling in' the bottom of this cavity runs down shaft l6 supported in the bearing 41, and finally finds its way into the annular space 48 surrounding the shaft which annular space is connected via passage 49 with the'suction side of the compressor. This insures the lubrication of the bearing 41.

The compressed gases leaving the annular cavity 40 pass down the passage 45 and flnd egress at 46 into the chamber 2|. Part of these gases also pass out of the hole at 45a into the upper chamber 2la of the interior of the hermetically sealed unit so as to equalize the'pressure therein, it being understood that the upper chamber 2la is at the same pressure at all times as the chamber 2|.

A cap 50 is provided above the annular cavity 40. This cap is a running fit on the shaft It. It merely prevents the constant escape of a large quantity of mixture at this point. It does not From this'annular groove, the lubricant act as a gas tight seal, for the reason that in the construction shown in Figure 2, the casing I0 is provided with an upper casing 5| joined thereto by bolts 52, whereby all parts are hermetically sealed, the only openings being for the inlet pipe to the compressor and the outlet for the compressed gases communicating with the chamber 2|.

For the sake of illustration, machines have been shown in which the shafts are vertical, but the system of lubrication may be applied to a machine in which the shafts are horizontal, in-

would lie in a plane at right angles to the shaft either in front or back thereof, finally connecting with the outlet 46. As such modifications are obvious to one skilled in they art, they are not here shown nor described in detail.

Although the invention has been disclosed in connection with specific details of preferred embodiments thereof, it must be understood that such details are not intended to be limitative of the invention except in so far as set forth in the accompanying claims.

What is claimed is:

1. In apparatus of the class described, a casin a shaft projecting from said casing, a seal about said shaft wherebythe latter is .maintained in fluid tight relation to said casing, a compressor having a suction inlet and a discharge outlet, a chamber adjacent said shaft communicating directly within the casing with said outlet, a bearing for said shaft, a passage between said chamber and the interior of said bearing whereby lubricant may pass from said chamber into said bearing and lubricate the same, a passage communicating with the interior of said seal and said inlet whereby excess lubricant entering the interior of said seal will be drawn into said compressor, and an annular groove about said shaft connected to the suction side of said compressor whereby lubricant will be drawn along said shaftfrom said first chamber into said groove thereby lubricating the shaft.

2. In apparatus of the class described, a casing, a compressor having an end plate supported on said casing and forming therewith a. chamber adapted to enclose lubricant, a shaft for driving said compressor extending outward through the end plate thereof, a tubular member mounted in said end plate and having a flange extending lat- 'erally therefrom, sealing means carried on said groove connected to the suction side of'said compressor whereby lubricant may be drawn from said groove along said shaft and into said sealing means to lubricate the same and along said shaft in an opposite direction to lubricate the same. r

3. In apparatus of the class described, a'caslng enclosing a body of lubricant, a compressor having a shaftand bearings and adapted to discharge above said lubricant and thereby apply pressure thereto, said compressor having a suction intake extending outside said casing, means for admitting lubricant under the aforesaid pressure to one of the bearings of said compressor, and means for collecting lubricant from the discharge of said compressor before said discharge enters said casing and applying said collected lubricant to a bearing of said compressor, said means including a member having an annular space therein surrounding the bearing and connected to the suction-side of the compressor whereby lubricant is drawn along the compressor shaft from said lubricant collecting means into said annular space thereby lubricating the bearing.

4. In apparatus of the class described, a compressor having a shaft and a bearing therefor, means including a-sump directly surrounding said shaft and in direct fluid communication therewith and with said bearing into which said compressor discharges, for applying lubricant to said bearing, said bearing having an annular interior groove surrounding said shaft and in fluid communication with the suction side of said compressor whereby lubricant may be drawn from said sump along said shaft thereby lubricating the same, a discharge duct connected to said sump adapted to deliver excess lubricant to a point below said annular interior groove, and a body of of lubricant separate from said sump for supplying same with lubricant.

5. In apparatus of the class described, a casing adapted to hold a body of lubricant under pressure, a compressor in said casing having a shaft,

a member forming a sump adapted to receive lubricant and positioned about said bearing and shaft, a passage between the discharge outlet of said compressor and said sump whereby all of thedischarge. including lubricant from the compressor is conveyed to said sump and lubricant accumulates therein, a passage from said sump to the space within said casing above said body of lubricant, and a bearing for said shaft having an annular cutaway portion surrounding the shaft and connected to the suction side of the compressor whereby lubricant may be withdrawn from said sump along said shaft and into said cutaway portion, thereby lubricating said bearing.

6. In apparatus of the class described, a casing adapted to hold lubricant under pressure, a compressor in said casing having a stationary body portion, front and rear endplates connected to said body portion, bearings in said end plates, a shaft for said compressor, passages in said body portion and front end plate whereby all of the discharge from said compressor is conducted to the outer end of the bearing therein, means whereby lubricant discharged at the outer end of said frontbearing may be drawn therethr'ol'igh casing, and means for supplying said last lubricant to the bearing in the rear end plate of said compressor.

WILLIAM EDWARD RICHARD.

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